Not really all that hard to understand. Two solvents used in the manufacturing of plastics with similar characteristics, neither proven safe to ingest, being used in the manufacture of an item that is not intended to be ingested. Design calls for one solvent, manufacturer substitutes what is generally considered an equivalent. The only problem is that while neither is safe to ingest, one is known to be unsafe, and the item, while not intended to be ingested, actually is likely to be ingested. This is typical of the kind of disconnect when the design company is separate from the manufacturing company.